Condensers and boilers ordinarily have a multiplicity of tubes within a shell fashioned from metal plate material apertured to accept the terminal of the tubes, the latter projecting slightly exteriorly of the plate. It has been the customary procedure in manufacturing such condensers and boilers to use a hand-held torch or electric welder to accomplish the welding of these terminals to the plate. With practice, a workman can make a strong, satisfactory weld around each terminal but it is strenuous, tiring work and the welds are always non-uniform and sometimes faulty. There is a need, therefore, for a substantially automatic tube welder which can be quickly and easily shifted by hand from terminal to terminal, satisfactorily rigid and stable in its operative position and capable of making rapid and uniform welds, while requiring the attention of only relatively unskilled workmen.